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Arid Land Geography ›› 2022, Vol. 45 ›› Issue (5): 1370-1380.doi: 10.12118/j.issn.1000-6060.2021.599

• Climate Change • Previous Articles     Next Articles

Variation of snow cover days and topographic differentiation in Sanjiangyuan area from 2001 to 2020

CAO Xiaoyun1,2(),XIAO Jianshe1,2(),HAO Xiaohua3,SHI Feifei1,2,4,LIU Zhiyuan1,2,LI Suyun1,2   

  1. 1. Key Laboratory of Disaster Prevention and Mitigation of Qinghai Province, Xining 810001, Qinghai, China
    2. Institute of Qinghai Meteorological Science Research, Xining 810001, Qinghai, China
    3. Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730099, Gansu, China
    4. School of Geographical Sciences, Qinghai Normal University, Xining 810001, Qinghai, China
  • Received:2021-12-14 Revised:2022-02-07 Online:2022-09-25 Published:2022-10-20
  • Contact: Jianshe XIAO E-mail:xiaoyun_cao@126.com;xiaojianshe@126.com

Abstract:

In this work, based on daily cloudless remote sensing of snow cover and meteorological observation data, the horizontal and vertical distribution characteristics of and variations in snow cover days in the Sanjiangyuan (Three Rivers Headwaters) area of Qinghai, China from 2001 to 2020 are analyzed; the correlation between snow cover days and temperature and precipitation are also analyzed using the same data source. The results showed that: (1) From 2001 to 2020, the number of snow cover days in Sanjiangyuan area was higher in the west and lower in the east; the number of snow cover days is higher in the high-altitude mountain regions than in the basin plain. The average snow cover days in high-altitude mountains was generally greater than 200 d. The number of snow cover days in 85.48% of the areas showed an increasing tendency (with fluctuations), increasing by 16.59%, and the average rate of increase was 0.98 d·a-1. (2) There were clear differences in the number of snow cover days and their variation over the study period based on the altitude and aspectality of the study region. The number of snow cover days increases exponentially with increasing altitude: at low altitude (<3.0 km) the snow covered area was found to be small and shows a decreasing trend. At low altitudes the number of snow cover days rate of reduction accelerates with increasing altitude. At high-altitude areas the number of snow cover days is larger and shows an increasing tendency, but the increase rate in the number of snow cover days at heights of more than 4.4 km decreases as the altitude increases. In the elevation range 5.5-6.0 km, the number of snow covered days showed a tendency to decrease. The number of snow cover days onnorth-facing slopes is greater than that on south-facing slopes; west-facing slopes show a larger number of snow cover days than east-facing slopes. Northwest-facing slopes have the largest number of snow cover days with 78.30 d. The rate at which the number of snow covered days increases was found to be greatest for west-facing slopes (1.04 d·a-1). (3) The warm and humid climatic characteristics of the Sanjiangyuan area over the past 20 years were the main causes of the change in the number of snow cover days; precipitation was also a primary driving factor, and the increase of snow cover days was closely related to the increase in precipitation; snow cover days at high altitudes are more dependent on precipitation.

Key words: Sanjiangyuan area, snow cover days, climate change, topographic differentiation